Controller for electric motors



(No Model.)

E. W. G. G. HOFPMANN CONTROLLER FOR ELECTRIC MOTORS.

No. 598,991. Patented Feb. 15, 1898.

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UNITED STATES PATENT OEEIcE.

ERNST WILHELM GUSTAV CARL HOFFMANN, OF CIIARLOTTENBURG, GER- MANY, ASSIGNOR TO THE SIEMENS & HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS.

CONTROLLER FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 598,991, dated February 15, 1898.

Application filed December 29, 1897. 8erial No. 664,387. (No model.) Patented in Germany November 16, 1895, No. 88,586; in fiweden April 14, 1896,1Io. 8,064,- in Switzerland April 14, 1896, No, 11,973, in England April 17, 1896, No. 8,141; in Norway April 18, 1896, No. 5,196,- in Belgium April 18, 1896,N0, 120,939 in France April 20,1896, No- 225,687; in Italy June 8, 1896,110. 41,375; in Austria June 24, 1896, N0. 46/Z,549, and in Denmark January 21,1897, No. 980.

To (tZZ whom it may concern: Be it known that I, ERNST WILHELM Gus- TAV CARL IIOFFMANN, a subject of the Emperor of Germany, residing at Charlottenburg, 5 Germany, have invented new and useful Improvements in Controllers for Electric Motors, (Case No. 80,) of which the following is a specification, reference being had to the accompanying drawings, forming a part of IO the specification, for which Letters Patent have been granted in Germany, No. 88,586, dated November 16, 1895; in France, No. 225,687, dated April 20, 1896; in Belgium, No. 120,939, dated April 18, 1896; in Italy, No. 41,375, dated June 8, 1896; in Switzerland, No. 11,973, dated April 14, 1896; in Austria, No. 46/2,549, dated June 24, 1896; in Norway, No. 5,196, dated April 18, 1896; in Denmark, No. 930, dated January 21, 1897; in 20 Great Britain, No. 8,141, dated April 17-, 1896, and in Sweden, No. 8,064, dated April 14, 1896. My invention relates to improvements in controllers for electric motors, and has for its object the provision of apparatus especially designed for the efficient and partially-automatic control of the motor-circuits of an electricallypropelled car or vehicle in a manner avoiding the arcing frequently attendant upon the control of heavy currents.

lVhen electric motors are switched from series to parallel circuit arrangement with one another, or vice versa, it is necessary either to open the motor-circuit or to shorteircuit momentarily one of said motors. In either event violent sparking is liable to occur unless great care is exercised in regulating the rheostat connected with the motor, such sparking obviously being detrimental to these parts. Sparking, however, may be mined amount of resistance in circuit, but

which is maintained in its adjusted position during the time that the switching apparatus is inoperative.

My invention will be more readily understood by reference to the accompanying draw ings, wherein- Figure 1 is a vertical sectional view of my improved controller, the same being somewhat diagrammatically shown for the sake of clearness. Fig. 2 is a cross-sectional view on line 2 2 of Fig. 1,illustrating the connection between the switching apparatus and the rheostat; and Fig. 3 is a similar view on line 3 3 of Fig, 1, illustrating one of the switch ing-arms of the controller.

The same letters of reference are used to designate like parts throughout the several figures of the drawings.

Mounted within the casing a are the shafts b 0, respectively connected with the switching-arms d of the controller and with the rheostat e. The shaft 6 is provided with a crank or handle Z), and the shaft 0 is provided with a hand-wheel 0', whereby said shafts are adapted, respectively, to be rotated. Upon the upper part of the shafts are respectively provided the recessed disk 6 and the ratchetwheel 0 the teeth of which are engaged by the pivoted catch f, which is normally maintained in engagement with said ratchet-wheel by means of the spring f. A roller f provided upon the opposite end of the said catch, is maintained in engagement with the re cessed disk 6 the said disk being adapted to withdraw the catch f from engagement with the ratchet-wheel 0 when the roller is brought in contact with the non-recessed faces of the disk IF. A spring g, acting upon the sector g, connected with the shaft 0, is adapted to rotate said shaft to its first position of adj ustment when the ratchet-wheel is thus released and thereby cut in the full amount of resistance connected in the rheostat. The shaftb also carries five cams or eccentric parts d, which are adapted to actuate the corresponding switch-arms d, controlling the 1notor-circuits through the medium of the engaging roller (1 provided upon the said arms.

The switch-arms are provided with contacts d d, each switch-arm thus controlling one of the several circuit changes of the device. The cams cl are keyed upon the shaft 12 in different angular positions which correspond to the five operative positions of the said device herein shown and described. \Vhen one of the cams is rotated in the position shown in Fig. 3, the pivoted switcharm d is moved upward and the contacts 61 d are separated, thereby opening the correspondingmotor-circuit. The five operative positions of the crank or controller handle may be connected, for example, to effect the following circuit changes: Position 1 maintains the motor-circuits open through the controller, position 2 serves to connect the motors in series, and position 3 to connect the same in parallel. Moving the crank 12 from position 1 in a reverse direction to position 4 will serve to connect the motors in parallel and secure a braking action, while the movement to position 5 will connect said motors in series and reverse the direction of their rotation.

The several circuit changes, above indicated are taken arbitrarily as examples, inasmuch as the switching may be adjusted to the individual needs of the controlled circuits. Furthermore, any other suitable switching device may be substituted for the several switch-arms d, the same being connected in a well-known manner with the shaft 1) and adapted to be actuated thereby. It will be understood, of course, that in each instance, as the position of the crank I) is altered, the full resistance is automatically out into circuit through the medium of the spring g acting upon the shaft 0. Thus the resistance connected in circuit and the several switching movements of the crank are made interdependent, as the release of the shaft 0 is antomatically effected by the disk b each time the controller-handle is altered in its position. The resistance of the rheostat is accordingly at once cut into circuit, since the spring 9 is placed under tension whenever the handwheel 0 is moved to cut resistance out of circuit. lVhile the crank b is maintained in any one of its operative positions, it is apparent that the hand-wheel cmay be independently I have purposely omitted from the drawings for the sake of clearness complete representation of the several rheostat resistancecoils, as well as the indication of circuit arrangements as adverted to above, since these are matters well known to those skilled in the art and will be at once supplied by such persons when the specific needs of a circuit are made apparent.

It will be seen that the controller above described is capable of numerous modifications without departing from the spirit of my in- 1 vention, and I do not desire to be understood as limiting myself to the precise apparatus or arrangement of parts herein set forth; but,

Having now explained my invention 1n connection with its preferred embodiment, I claim as new, and desire to secure by these Letters Patent, the following:

1. The combination in a controller for electrical apparatus, with a controller part Z) having suitable contact parts connected therewith for effecting the necessary circuit changes, of a rheostat, a part c controlling the resistance of said rheostat connected in circuit, and means for automatically cutting a predetermined amount of. resistance into circuit when the movement of said part is effected, substantially as. described.

2. In a circuit-controlling device, the combination with a controller part b, means associated therewith for effecting the several switching arrangements of said controller upon the movement of said part, a rheostat 6 associated with said controller, a rheostat part c, the movement of which is adapted to effect the control of the rheostat resistance connected in circuit, and means associated therewith for effecting the automatic insertion of a predetermined amount of said resistance when part b is moved from one operative position to another, substantially as described.

3. In a circuit-controller for electrical apparatus, the combination with a part b, the actuation of which is adapted to effect an alteration inthe switching arrangement of the connected circuits, of a rheostat c, a controlling part 0 associated therewith, means for normally securing the inclusion in circuit of a predetermined amount of resistance, a disk b a ratchet-wheel 0 respectively connected with the said parts Z) and c, and a catch f in engagement with the said disk and wheel adapted to be actuated upon the movement of part b to release said ratchet-wheel, whereupon resistance is automatically cut into circuit, substantially as described.

4. In a circuit-controller and rheostat, the combination with a shaft 1), the rotation of which is adapted to effect the movement of a switch part d, thereby effecting the control of a connected circuit, of a rheostat e, a shaft '0, the movement of which controls the resistance of said rheostat connected in circuit, a

disk W, a ratchet 0 respectively provided when said ratchet is thus released, substanupon the said shafts b and c, a catch f in entially as described. 1o gagement with said ratchet adapted to be 210- In testimony whereof I affix my signature tuated by the disk 12 upon the movement of in the presence of two Witnesses.

the shaft 1) from one operative position to an- ERNST WILHELM GUSTAV CARL HOFFMANN. other, and means associated with the said Witnesses:

rheostat for automatically cutting; a prede- HENRY HARPER,

terinined amount of resistance into circuit CHARLES H. DAY. 

